In his latest piece for The New Yorker, Malcolm Gladwell reviews two recently published books. The first – The Sports Gene, by David Epstein – is about the genetic and phenotypic gifts of elite athletes; the second – Tyler Hamilton'sThe Secret Race – about the widespread use of performance enhancing drugs among Tour de France cyclists.

Three: Science has the power to elevate athletes to an unprecedented plane of performance. So why don't we let it?

It's a fascinating review. He goes on to write:

Toward the end of “The Sports Gene” (Penguin/Current), David Epstein makes his way to a remote corner of Finland to visit a man named Eero Mäntyranta. Mäntyranta lives in a small house next to a lake, among the pine and spruce trees north of the Arctic Circle. He is in his seventies. There is a statue of him in the nearby village. “Everything about him has a certain width to it,” Epstein writes. “The bulbous nose in the middle of a softly rounded face. His thick fingers, broad jaw, and a barrel chest covered by a red knit sweater with a stern-faced reindeer across the middle. He is a remarkable-looking man.” What’s most remarkable is the color of his face. It is a “shade of cardinal, mottled in places with purple,” and evocative of “the hue of the red paint that comes from this region’s iron-rich soil.”

Mäntyranta carries a rare genetic mutation. His DNA has an anomaly that causes his bone marrow to overproduce red blood cells. That accounts for the color of his skin, and also for his extraordinary career as a competitive cross-country skier. In cross-country skiing, athletes propel themselves over distances of ten and twenty miles—a physical challenge that places intense demands on the ability of their red blood cells to deliver oxygen to their muscles. Mäntyranta, by virtue of his unique physiology, had something like sixty-five per cent more red blood cells than the normal adult male. In the 1960, 1964, and 1968 Winter Olympic Games, he won a total of seven medals—three golds, two silvers, and two bronzes—and in the same period he also won two world-championship victories in the thirty-kilometre race. In the 1964 Olympics, he beat his closest competitor in the fifteen-kilometre race by forty seconds, a margin of victory, Epstein says, “never equaled in that event at the Olympics before or since.”

In “The Sports Gene,” there are countless tales like this, examples of all the ways that the greatest athletes are different from the rest of us. They respond more effectively to training. The shape of their bodies is optimized for certain kinds of athletic activities. They carry genes that put them far ahead of ordinary athletes.

Epstein tells the story of Donald Thomas, who on the seventh high jump of his life cleared 7' 3.25"—practically a world-class height. The next year, after a grand total of eight months of training, Thomas won the world championships. How did he do it? He was blessed, among other things, with unusually long legs and a strikingly long Achilles tendon—ten and a quarter inches in length—which acted as a kind of spring, catapulting him high into the air when he planted his foot for a jump. (Kangaroos have long tendons as well, Epstein tell us, which is what gives them their special hop.)

Why do so many of the world’s best distance runners come from Kenya and Ethiopia? The answer, Epstein explains, begins with weight. A runner needs not just to be skinny but—more specifically—to have skinny calves and ankles, because every extra pound carried on your extremities costs more than a pound carried on your torso. That’s why shaving even a few ounces off a pair of running shoes can have a significant effect. Runners from the Kalenjin tribe, in Kenya—where the majority of the country’s best runners come from—turn out to be skinny in exactly this way. Epstein cites a study comparing Kalenjins with Danes; the Kalenjins were shorter and had longer legs, and their lower legs were nearly apound lighter. That translates to eight per cent less energy consumed per kilometre. (For evidence of the peculiar Kalenjin lower leg, look up pictures of the great Kenyan miler Asbel Kiprop, a tall and elegant man who runs on what appear to be two ebony-colored pencils.) According to Epstein, there’s an evolutionary explanation for all this: hot and dry environments favor very thin, long-limbed frames, which are easy to cool, just as cold climates favor thick, squat bodies, which are better at conserving heat.

Distance runners also get a big advantage from living at high altitudes, where the body is typically forced to compensate for the lack of oxygen by producing extra red blood cells. Not too high up, mind you. In the Andes, for example, the air is too rarefied for the kind of workouts necessary to be a world-class runner. The optimal range is six to nine thousand feet. The best runners in Ethiopia and Kenya come from the ridges of the Rift Valley, which, Epstein writes, are “plumb in the sweet spot.” When Kenyans compete against Europeans or North Americans, the Kenyans come to the track with an enormous head start.

What we are watching when we watch élite sports, then, is a contest among wildly disparate groups of people, who approach the starting line with an uneven set of genetic endowments and natural advantages. There will be Donald Thomases who barely have to train, and there will be Eero Mäntyrantas, who carry around in their blood, by dumb genetic luck, the ability to finish forty seconds ahead of their competitors. Élite sports supply, as Epstein puts it, a “splendid stage for the fantastic menagerie that is human biological diversity.” The menagerie is what makes sports fascinating. But it has also burdened high-level competition with a contradiction. We want sports to be fair and we take elaborate measures to make sure that no one competitor has an advantage over any other. But how can a fantastic menagerie ever be a contest among equals?